1. Field of the Invention
The present invention relates to a turbofan and a method of manufacturing the same, and more particularly, to a turbofan and a method of manufacturing the same, which facilitates a manufacturing process and reduces a defective fraction of products during the manufacturing process of the turbofan.
2. Description of the Related Art
Generally, a turbofan is a kind of centrifugal fan, which is adapted to blow air generated from rotating blades. As shown in FIG. 1, the turbofan comprises a circular rotating plate 1 having a central hub 1a to which a rotating shaft of a drive motor (not shown) couples, a plurality of blades 2 which are radially disposed at a periphery of the circular rotating plate 1 with regular intervals therebetween such that the plurality of blades 2 are positioned to be perpendicular to the circular rotating plate 1, and a ring-shaped shroud 3 joining to free ends of the plurality of blades 2 to support the plurality of blades 2.
The turbofan is usually produced by a plastic injection molding process. Since a configuration of the turbofan is complicated, the turbofan is provided with a number of undercuts on the plurality of blades 2 thereof, thereby causing a separation of a mold therefrom to be difficult. Thus, the turbofan is hard to integrally mold by only one molding process. To overcome this disadvantage, a conventional turbofan is produced in such a way that a part A, in which the circular rotating plate 1 and the plurality of blades 2 are integrally molded, and the shroud part 4 are first molded by separate molds, as shown in FIG. 2, and the part A and the shroud part 4 are combined with each other by an ultrasonic fusion or a heat fusion in a subsequent procedure.
In a conventional process of manufacturing turbofans, since a procedure of combining the shroud part 4 with ends 2a of the plurality of blades 2 by the ultrasonic fusion or the heat fusion is not precisely achieved, a problem occurs that a high portion of the product is defective. More specifically, since the ring-shaped shroud 3 and the ends 2a of the plurality of blades 2 joining to the ring-shaped shroud 3 have inclined and curved surfaces corresponding to each other, the plurality of blades 2 deviate from the ring-shaped shroud 3 in inward or outward directions during a joining procedure. Thus, to precisely join the plurality of blades 2 to desired portions of the ring-shaped shroud 3 is difficult. Accordingly, where a joined state of the plurality of blades 2 and the ring-shaped shroud 3 is not correct, a bonding strength of the plurality of blades 2 and the ring-shaped shroud 3 is lowered and a performance of the turbofan is lowered.